Strands of Time
by Shadow Riser
Summary: The final battle doesn't go as planned. At the moment of victory, time sand is thrown onto the dueling pair and Harry wakes up in Tom Riddle's Hogwarts, with no way of getting back. He must find a way to return to his time, all while fending off Riddle's suspicions and amid the threat of Grindelwald's powerful army, whose leader seems to have a horribly familiar fixation with him.
1. Chapter 1 - The Sands of Time

**Disclaimer: I do not own Harry Potter**

 **Enjoy!**

* * *

The war had not ended how anyone had envisioned.

Harry, Ron and Hermione had returned to Hogwarts for the final battle. Hope had arrived, giving the fighters courage, courage enough to keep fighting even as their companions were cut down one by one.

The courage turned to despair when Voldemort appeared with the body of their savior being carried by the sobbing half-giant, but Harry had appeared once again, defying death and reason another time.

As Voldemort and Harry shouted their spells - one deadly, the other child's play - the spells connected once more, the green light arcing towards Voldemort -

And then a death eater had yelled something, thrown an object at the two, and there was whirl of golden light tinged with green and red, and both men disappeared.

The war had ended, but their saviour was gone.

* * *

Harry woke up confused.

He'd been Hogwarts - with Voldemort -

He sat up straight, eyes opening.

He appeared to be in the hospital wing, but the nurse bumbling towards him bore no comforting smile like Madam Pomfrey.

"Where am I?" he asked.

The healer clicked her tongue. "I think it's me who should be asking the questions, young man. Was it a joke?"

Harry blinked. "What?"

The witch waved her wand over him, nodding as if satisfied. She gave him a long, considering glance before answering. "You appeared in the middle of the Great Hall at breakfast, and hit your head. I suppose amnesia was always a possibility - do you remember anything?" Her tone had softened slightly.

Harry shook his head hesitantly, deciding that playing along with amnesia was probably the best option until he worked out where the heck he was.

"Your name?" she pushed.

"Harry," he responded before thinking. Crap.

But there was no recognition in her eyes. "Harry what?"

A last name. Any random name. "… Smith."

If she noticed his hesitation she didn't say. "Right, Mr Smith, you should rest. I'll inform Headmaster Dippet that you're awake, but I'll hold him off questioning until you're well rested. Generally, amnesia is only temporary - you'll get your memory back in no time." She gave him a nod and bustled off, missing the astonished expression on Harry's face. Professor Dippet.

Everything fell into place in Harry's head and he groaned.

The Death Eater had thrown time sand at them, sending them back - and he was apparently in Tom Riddle's Hogwarts.

No, Harry corrected himself. _Might_ be in Riddle's time. For all he knew, Dippet could have been headmaster for a hundred years; the chances of being in the young Dark Lord's life span was low, let alone in school with him …

"Hello," a voice from the bed adjacent to Harry's called.

Harry glanced up and his heart nearly stopped.

Sirius was lying in the bed, hair as unruly as ever, eyes grey and careless -

No. This wasn't Sirius. This boy's face was sharper, his nose bigger.

"I'm Alphard Black, you're Harry Smith, right?"

Shit.

Wasn't Alphard the uncle Sirius had mentioned gave him some gold? And was blasted off the tapestry, Harry remembered.

He still could be in a non-Tom-Riddle-Hogwarts. Sirius would have been - Harry ignored the stab of ice going through his chest at the reminder - thirty-eight if he'd - if he'd lived at the time Harry had just been in - and Merlin if this wasn't hurting his head already - which meant he'd been born in … 1959. Riddle was born in 1926, so Alphard would have to be born … six years earlier in order to have a first-year Riddle? Harry groaned. "What year is it?" he asked tiredly.

Alphard raised his eyebrows. "You've really lost your memory? It's 1943. September tenth to be precise."

1943\. So Riddle would be … Harry groaned, sinking back into his pillows. Riddle would be seventeen, in seventh year.

"Is that bad?" Alphard looked far too amused, and Harry was reminded with another sharp pang in his chest of how like Sirius he looked.

"No," Harry muttered, trying for a smile. "Just unexpected."

Alphard nodded. "So what amnesia have you got? There's different types, aren't there - partial and total and one where you still know how to do stuff - gosh, wouldn't it be awful if you got partial amnesia before exams and forgot everything?"

He paused, looking at Harry expectantly. Harry shrugged. "I s'pose so."

"Which one have you got then?" Alphard leaned forward.

"Erm." Should he pretend to have forgotten everything? No, he'd already said his name … "I remember stuff like my name and how to do magic but nothing else, not really."

"Wow."

The matron bustled back in then, saying sharply, "Leave Mr Smith alone, Black. I don't want to hear any talking." She glared at them both until they dropped their eyes. " _Nox_."

The room dark, Harry lay back down on his pillow and shut his eyes. He may as well try to get some sleep -

"Psst."

Harry sighed. "What?"

"Do you think you'll be joining lesson?" Alphard whispered.

"I guess. What else would they do with me?"

Alphard made a sound of acknowledgment. "How old are you?"

"Seventeen." Harry quickly added, "I think."

He could nearly hear Alphard's smile. "You'll be in our year then, with Tom -"

"Shh!" The hiss came from over by the door to the matron's rooms. "Or I'll stun you, Black, I swear."

Alphard grumbled but said nothing more, and the room was soon filled by his soft snores. Harry, however, could not sleep at all, thoughts of "Tom" running through. By this point he would have released the basilisk, killed his parents - that was his sixth year? No, maybe it was seventh … It was done over the summer in any case, so the Dark-Lord-to-be would already have one horcrux, possibly two.

Alphard had sounded happy when he mentioned him though. So Riddle must not seem like a total psychopath yet - or maybe Alphard was a follower? He was a Black after all - but no, Harry quashed that thought with another burst of guilt. Sirius had been a Black. Andromeda was a Black. And Sirius hadn't mentioned Alphard in anything but a positive light; if he'd been a death eater, even for a short time, Sirius would have said, would have let that colour his tone.

But that meant Riddle was obviously still using his masks, still the model student, even at this point with the weight of Dumbledore's suspicion on him and a horcrux on his finger.

Merlin, it was going to be so weird to see Dumbledore alive. Didn't he have red hair at this point? A small smile appeared before turning sad again. McGonagall … would she be a student? Maybe not. Slughorn was teaching, though, with a full head of hair if Harry remembered the memory correctly.

He needed to get back to his own time. But he couldn't tell anyone - he'd have to work it out himself, in an age where there were no timeturners, and any research would be in the Department of Mysteries. He'd have to break in, or work his way into infiltrating it. But the later would take far longer.

And then he had to deal with Tom Riddle.

If Riddle took even enough notice of him to recognise him seventy years later, it could give the future Voldemort too much information and create one of those time-loop-thingies Hermione had talked about.

He missed her already.

Shifting onto his side, Harry curled up in the covers. He would need his sleep for tomorrow. Letting his mind relax, Harry started the Occlumency he'd been almost successful with a while ago, before he had dropped the feeble attempt Hermione had coerced him into. It was useful for getting to sleep.

* * *

Voldemort hit the ground with a thump, but sprang to his feet, wand up. The Potter boy had -the wand - was he dead?!

He was on a hillside, wind biting at his skin. Far too cold for Britain. Not exactly what he'd imagined the afterlife to be.

One of his followers had done something, of that much he was certain. It had been a kind of sand … time sand.

So where was he?

Disguising himself with a flick of his wand - which still wasn't working properly, he noted with dissatisfaction, Potter had been right abut the ownership - he started off towards the cluster of buildings he could see in the distance. He couldn't risk Apparating in case he chose a destination too far away - he could do up to a thousand miles, but any further risked splinching.

It took him a few hours to reach the dwellings, which were horribly muggle. Voldemort sneered as he passed a couple of beggars, one child and one a young woman, who looked at him with mouths gaping.

"Tell me what year it is," he commanded.

The woman looked at him blankly. "Was?" she asked.

"What. Year. Is. It," he repeated, fingers twitching on his wand.

"Ich verstehe nicht," she said, shaking her head. "Bitte?" she held out her begging bowl.

German. No matter. " _Legilimens_ ," he said, and stepped back after a minute. The images running trough the woman's mind were ones of war, of losing, of a dead husband and harsh measures, of money being worse than useless but she had nothing to do but beg for food. From what he had gathered, it should be around nineteen twenty-five.

Nineteen-twenty-five in Germany … an idea took root in Voldemort's twisted mind, and a smile crept onto his face. He barely noticed as the muggle shank back, pulling her child with her.

Focusing on his destination, he Disapparated with a faint crack, leaving the two witnesses staring fearfully at the air.

* * *

 **So ... what d'ya think? I know the Harry-goes-back-to-Tom-Riddle's-Hogwarts is not an original idea but hopefully the addition of throwing Voldie back as well mixes it up a bit.**

 **This one has vaguely more planning than HiPS, but HiPS is still my primary story. Currently I'm just writing random parts of one-shots, full length ones, ideas - it's a right mess.**

 **Anyway, hope you enjoyed. The amount of attention this gets depends on both my inclination and your opinion, so drop a review (pretty please?) :P**

 **Oh, and the German is purely off the trusty google translate so please say if I've got it wrong. Thanks!**


	2. Chapter 2 - Into the Dungeons

**Hi Guys!**

 **So I know it's literally been over a year since I updated anything but I'm really going to try this summer to keep going with both this and HiPS. (A Levels now over and all that jazz).**

 **So enjoy, and apologies for any spelling/ syntax mistakes - I do go through it at least three times but this one's uploaded on iPad so a bit harder to edit without a mouse.**

* * *

Harry woke up as the curtains around his bed were dragged back with a sharp screech. "Headmaster Dippet wants to see you, Mr Smith," the matron said. "Do you feel alright?"

Squinting against the sudden light, Harry saw that Alphard's bed was empty. "Er - yes, ma'am."

Nodding in satisfaction, the nurse handed him a bundle of clothes. "Your shoes are under the bed." She pulled the curtains back again and Harry heard her office door click.

The bundle consisted of boxers, a white, stiff shirt, woolen trousers and a thick Hogwarts robe. Pulling them on, Harry grimaced at how the material rubbed at his skin; he far preferred his jeans, or even cotton robes, to this.

His shoes - battered black Converse, and wasn't that a ridiculous pair to wear when fighting the Dark Lord - had been cleaned, and had a burn mark on the sole of one, but seemed fine.

"Madam …" What was her name? She hadn't said.

The healer came out of the office, giving him a once-over, her lip curling sligtly at his shoes and sticking-up hair. "The headmaster's office is on the seventh floor, along the corridor with the portrait of Unicules the Unicorn - _Partem_ ," she said suddenly, and a purple-hued spell washed over Harry, leaving him with the urge to go left. A direction charm?

"That'll lead you there, Mr Smith. If you get a headache or feel confused, return here immediately."

Harry nodded and followed the charm, his feet carrying down the familiar-but-not corridoors. It must have been during lessons, as the only students he came across were two Hufflepuffs having a game of dominoes in a window ledge. Or actually - it was quite dull outside, so perhaps it was evening.

Nothing was crubled, nothing broken, and Harry was struck by a wave of deep sadness as he remmbered how he'd last seen Hogwats. Except that was in the future.

How Hermione had coped with a Time-turner for a year he didn't know.

Dippet's office was in the same place as Dumbledore's - but of course it was, he'd seen it in Riddles's diary … Shit. Riddle. He'd almost forgotten.

The gargoyle stood there uninviting. "Erm. I'm Harry Smith," he stated, and it moved around to reveal the staircase.

The griffin knocker was there too, and Harry almost expected to see the spindly instruments of Dumbledore's office, but a voice called "enter" - and wasn't that familiar?

Harry had to fight to keep his expression neutral as he saw an aubern-haired Dumblesdore sitting at the side of the room.

Tearing his eyes away to Dippet, who was sat th desk, Harry cleared his throat. "I'm Harry Smith, Professors."

"Yes, yes - do sit down," Dippet gestured to the chair in front of the desk. "Now," he continued, "I understand you have completely lost your memory?" There was a faint note of incredulity in the headmaster's voice and Harry focussed on making his expresson as sincere and trubles as possile. "Yes, sir, unfortunately. Can you get me it back?"

Dumbledore's whimsical voice floated over from behind, and Harry stiffened. "The ways of the mind are a mystery to most even now - I'm afraid that without knowing the cause for sure there is little we can do but wait."

Harry nodded, trying to look disappointed.

"Now," Dippet said, smiing, "We must see where you are in your magical education. Can you cast a levitation charm?"

Harry followed Dippet's requests, which got steadily harder, until he realised the headmaster was looking slightly taken aback. Damn. He'd just done … oh. Several sligtly dark curses and a patronus. Without blinking. Training paid off, he supposed, but he hadn't wanted to raise supicions so soon.

He adopted an unsure look at the nxt spell, and Dippet stopped, saying, "Well, you're certinly able! Now, as for your house … There's not much point sorting you in front of the school, so - Albus, could you-?"

"Certainly." Dumbledore picked the old hat from its perch on the top of the bookcase and handed it to Harry. "Just try it on," he instructed.

Plopping the Sorting Hat on - it didn't go over his ears this time at least - Harry closed his eyes.

 _Hmm_ , the hat said. _Very interesting. I've sorted you already …_

 _Please don't tell,_ Harry asked silently.

The hat chuckled. _I won't, don't worry, but - my goodness, this will be a interesting year … Now, where to put you?_

 _Gryffindor would be nice_ , Harry suggested.

 _No, you are no longer a Gryffindor,_ the hat said decisively. Sensing Harry's shock, it added, _you're brave enough still, but you have learnt how to hide, how to have fun, how to hurt -_

 _No,_ Harry whined, suddenly seeing where this was going -

 _SLYTERIN!_ The hat said, a slightly gleeful note in its voice.

Dumbledore took the hat off Harry, who glared at it before accepting the green and silver tie Dippet was holding out to him. "Excellent!" the headmaster said, grinning. "The Slytherin dormitories are in the dungeons - Phineas, could you go and fetch the Head Boy? He's in Slytherin," he added to Harry after Phineas Nigellus slid out of his portrait, "and a model student."

Head boy … there was a small sinking feeling in Harry's stomach, which acentuated as the door swung open to reveal Tom Riddle in all his seventeen-year-old glory, slightly waved hair perfectly styled and an expression of sickening saintliness hiding the darkness Harry knew the boy's soul - or what was left of it - held.

"What could I do for you, Professors?" Riddle asked, eyes sweeping over Harry.

Dippet smiled fondly, and Harry resited the urge to mime vomitting. "This is Mister Harry Smith," he said, Harry saw Riddle's lips curl very slightly at the name, "he had lost his memory unfortunately but has been sorted into Slytherin. I trust you will take care of him?"

"Of course, headmaster." Rissle held out his hand. "Tom Riddle, pleased to meet you."

Harry shook the proffered hand, keeping his grip light. "Harry Smith." If he could be uninteresting, perhaps …

"So which year are you then … Harry?" Riddle asked.

Harry hesitated. Was he supposed to know? "I'm seventeen, eighteen in July," and damn, why had he just given out his real birthday? Remembering his amnesia, he frowned and rubbed his nose. "At least, I think so."

Riddle nodded. "Seventh year then - is he advanced enough with the curriculum, Professor Dippet?" The Slytherin's voice was the perfect mixture of confidence and deference - Harry could see why he had gained followers with such ease in his early years.

"Oh, yes indeed Tom, almost as good as you!" The headmaster said in a conspiring tone. Harry wouldn't have been surprised if Dippet had added in a wink.

Riddle cast a discerning eye over him and Harry nearly groaned. So much for not getting noticed.

"What are we doing about possessions - clothes, wand -"

"I have a wand," Harry interjected quickly.

"-potions kit and textbooks?" Riddle continued as if Harry hadn't even spoke.

Dumbledore spoke up this time. "I will arrange a trip to Diagon Alley at the weekend. For now, Harry will have to share - I assume you are willing to, Tom?"

This time Harry saw it - the flickr of annoyance at the name he had been given.

Dumbledore continued: "He can of course pick up some robes and other clothes from lost property or the infirmary."

Riddle nodded - a sharp jerky movement - then spun on his heel, indicting for Harry to follow him. "Goodnight then, Professors."

"Goodnight, Tom, Mr Smith ," Dippet replied, and Harry followed the younger dark lord down the stairs.

Merlin, why did things like this always have to happen to him?

Harry followed Riddle down the stairs, then more stairs, then more - they reached the ground floor before Riddle spoke.

"So, Harry … have you ever been to Hogwarts before?"

Harry frowned. He'd been told he had 'amnesia'. "I don't know. I don't recognise anything."

Riddle nodded. "What do you remember from before you arrived?"

An interrogation then. Of course. He needed to remember to keep his story straight - though remembering nothing shouldn't be too hard. "Not much. I know my name, I know I'm right handed …" What else would he know? "I think I know my age and birthday and I remember how to do magic but I don't remember learning it."

Riddle nodded, his face impassive. "Well, then, a few things you should know: in Hogwarts, there are four houses, each with characterised with different attributes. You have been sorted into Slytherin, like me, which is known for housing students who are cunning and ambitious. The other houses are.."

Harry pretended to be interested in the very much shortened version of the history of Hogwarts, and was careful not to look like he knew where he was going when the young dark lord stopped in the middle of a corridor.

"The entrance to common room is here. You can tell which part of the wall it is because of the serpent etched on the flagstones," Riddle pointed downwards, and indeed once it had been pointed out Harry could see the faint engraved snake on the floor. "The password this month is Nobility, but it changes every second Sunday, with the new password posted on the notice board between eight and eleven on the Sunday evening."

What was it with Slytherin passwords being so up their own arse?

All eyes were on Harry as he stepped into the common room, conversation ceasing immediacy as the students saw who accompanied him.

"This is Harry Smith," Riddle said, and Harry could again just about detect the distaste for his name - presumably his first, as he was sure there were some pure bloods named Smith, but then again the Smiths were all Hufflepuff if he remembered correctly so it really could be either. He should have thought a bit harder before picking a name - but this wouldn't have been a problem if the stupid hat had just sorted him into Gryffindor again …

"He has lost his memory but will be staying at Hogwarts for the foreseeable future and has been sorted into Slytherin," Riddle continued, casting his gaze around the room where every few failed to look down in submission. "I trust you will make him welcome." The last part was said with so little emotion Harry could tell it was meant to put across that he didn't care in the slightest whether they welcomed Harry with open arms or knives.

"You will be in the seventh-year dorm, the same as me." Riddle jerked his head in a 'follow me' gesture and led Harry down a side door, deeper underground then he thought the caste went. Harry was glad to leave the prying eyes behind but couldn't help tensing up when he was once again alone with Riddle.

The room Riddle eventually led Harry into was spacious, with eight beds - one conspicuously devoid of belongings - and a window on the far side looking out into the lake, although in the evening gloom Harry could see nothing more than his own reflection in the glass.

"I will get the house elves to fetch you some spare robes for tomorrow." Riddle cast an eyes over Harry's current footwear. "You will need to get new ones and some new, appropriate footwear when the headmaster takes you to Diagon."

Harry just nodded. "Who else shares this room?"

Pointing to each bed in turn, Riddle rattled off: "Morgan Avery, Cyril Lestrange, Kit McGregor, Jarrett Nott, me, obviously, Alfred Rosier and Alphard Black."

So many names he had already fought. Harry suppressed a shiver. "What time do I need to get up in the morning?" He wanted to get into bed and close his curtains as soon as possible. And preferably not have to deal with Alphard when he came in.

"Breakfast is at seven thirty. If you want a shower I suggest getting up before seven."

Harry nodded, and Riddle seemed to take that as leave to go back to whatever he would be doing. "I will see you later, then," he said before turning on heel and leaving Harry alone.

Harry slumped onto the bed, letting himself relax for the first time since before the battle of Hogwarts. He sat there with his head in his hands for a full minute before casting a _tempus_ charm; it was half past eight. Early to go to bed, but he felt like he needed it.

First, however, Harry cast the protective charms Hermione had taught him - he forced himself not to think of her or anyone else he'd left - so that his curtains were warded against eavesdropping and would alert him if anyone else touched them.

Conjuring up a toothbrush, Harry was in the bathroom when a crack alerting him to the house elf which appeared by his bed. "Libby has bought Harry Smith his belongings and spare clothes, sir," the elf piped up, then dropped the bundle on the bed and Disapparated before Harry could thank her.

Unraveling the bundle, Harry was pleased to find his t-shirt and jeans he had arrived in freshly washed, as well as several pars of socks and underwear, some white shirts and several robes emblazoned with the Slytherin crest.

Too tired to do much, Harry shoved them into the drawer under the bed and striped down to boxers before getting onto bed. " _Nox_ ," he muttered, then stuck his wand under his pillow after casting an alarm for seven-twenty-five.

Despite his new surroundings, Harry was asleep in minutes, though his dreams were plagued with visions of Tom Riddle when he had last seen him in younger form: the Gants, the chamber of secrets and the orphanage memories all merging into one unsettling nightmare.

* * *

 **Again, will hopefully be updating HiPS soon - that ones just a lot more to read back through and plot!**

 **Edit 11/07/18 - checked over on laptop to fix some syntax mistakes (and thank you for the reviews!)**


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